SOD2 and breast cancer: Thus, the purpose of this exploratory candidate gene association study was to examine relationships between variation in genes involved in oxidative stress (CAT, GPX1, SEPP1, SOD1, and SOD2) and DNA repair (ERCC2, ERCC3, ERCC5, and PARP1) and pre-adjuvant therapy CF in postmenopausal women with early stage breast cancer.